2 lm77.c - Part of lm_sensors, Linux kernel modules for hardware
5 Copyright (c) 2004 Andras BALI <drewie@freemail.hu>
7 Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>. The LM77
8 is a temperature sensor and thermal window comparator with 0.5 deg
9 resolution made by National Semiconductor. Complete datasheet can be
10 obtained at their site:
11 http://www.national.com/pf/LM/LM77.html
13 This program is free software; you can redistribute it and/or modify
14 it under the terms of the GNU General Public License as published by
15 the Free Software Foundation; either version 2 of the License, or
16 (at your option) any later version.
18 This program is distributed in the hope that it will be useful,
19 but WITHOUT ANY WARRANTY; without even the implied warranty of
20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 GNU General Public License for more details.
23 You should have received a copy of the GNU General Public License
24 along with this program; if not, write to the Free Software
25 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28 #include <linux/module.h>
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/jiffies.h>
32 #include <linux/i2c.h>
33 #include <linux/hwmon.h>
34 #include <linux/hwmon-sysfs.h>
35 #include <linux/err.h>
36 #include <linux/mutex.h>
38 /* Addresses to scan */
39 static const unsigned short normal_i2c
[] = { 0x48, 0x49, 0x4a, 0x4b,
42 /* The LM77 registers */
43 #define LM77_REG_TEMP 0x00
44 #define LM77_REG_CONF 0x01
45 #define LM77_REG_TEMP_HYST 0x02
46 #define LM77_REG_TEMP_CRIT 0x03
47 #define LM77_REG_TEMP_MIN 0x04
48 #define LM77_REG_TEMP_MAX 0x05
50 /* Each client has this additional data */
52 struct device
*hwmon_dev
;
53 struct mutex update_lock
;
55 unsigned long last_updated
; /* In jiffies */
56 int temp_input
; /* Temperatures */
64 static int lm77_probe(struct i2c_client
*client
,
65 const struct i2c_device_id
*id
);
66 static int lm77_detect(struct i2c_client
*client
, struct i2c_board_info
*info
);
67 static void lm77_init_client(struct i2c_client
*client
);
68 static int lm77_remove(struct i2c_client
*client
);
69 static u16
lm77_read_value(struct i2c_client
*client
, u8 reg
);
70 static int lm77_write_value(struct i2c_client
*client
, u8 reg
, u16 value
);
72 static struct lm77_data
*lm77_update_device(struct device
*dev
);
75 static const struct i2c_device_id lm77_id
[] = {
79 MODULE_DEVICE_TABLE(i2c
, lm77_id
);
81 /* This is the driver that will be inserted */
82 static struct i2c_driver lm77_driver
= {
83 .class = I2C_CLASS_HWMON
,
88 .remove
= lm77_remove
,
90 .detect
= lm77_detect
,
91 .address_list
= normal_i2c
,
94 /* straight from the datasheet */
95 #define LM77_TEMP_MIN (-55000)
96 #define LM77_TEMP_MAX 125000
98 /* In the temperature registers, the low 3 bits are not part of the
99 temperature values; they are the status bits. */
100 static inline s16
LM77_TEMP_TO_REG(int temp
)
102 int ntemp
= SENSORS_LIMIT(temp
, LM77_TEMP_MIN
, LM77_TEMP_MAX
);
103 return (ntemp
/ 500) * 8;
106 static inline int LM77_TEMP_FROM_REG(s16 reg
)
108 return (reg
/ 8) * 500;
113 /* read routines for temperature limits */
114 #define show(value) \
115 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \
117 struct lm77_data *data = lm77_update_device(dev); \
118 return sprintf(buf, "%d\n", data->value); \
126 /* read routines for hysteresis values */
127 static ssize_t
show_temp_crit_hyst(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
129 struct lm77_data
*data
= lm77_update_device(dev
);
130 return sprintf(buf
, "%d\n", data
->temp_crit
- data
->temp_hyst
);
132 static ssize_t
show_temp_min_hyst(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
134 struct lm77_data
*data
= lm77_update_device(dev
);
135 return sprintf(buf
, "%d\n", data
->temp_min
+ data
->temp_hyst
);
137 static ssize_t
show_temp_max_hyst(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
139 struct lm77_data
*data
= lm77_update_device(dev
);
140 return sprintf(buf
, "%d\n", data
->temp_max
- data
->temp_hyst
);
144 #define set(value, reg) \
145 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \
147 struct i2c_client *client = to_i2c_client(dev); \
148 struct lm77_data *data = i2c_get_clientdata(client); \
149 long val = simple_strtol(buf, NULL, 10); \
151 mutex_lock(&data->update_lock); \
153 lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \
154 mutex_unlock(&data->update_lock); \
158 set(temp_min
, LM77_REG_TEMP_MIN
);
159 set(temp_max
, LM77_REG_TEMP_MAX
);
161 /* hysteresis is stored as a relative value on the chip, so it has to be
163 static ssize_t
set_temp_crit_hyst(struct device
*dev
, struct device_attribute
*attr
, const char *buf
, size_t count
)
165 struct i2c_client
*client
= to_i2c_client(dev
);
166 struct lm77_data
*data
= i2c_get_clientdata(client
);
167 unsigned long val
= simple_strtoul(buf
, NULL
, 10);
169 mutex_lock(&data
->update_lock
);
170 data
->temp_hyst
= data
->temp_crit
- val
;
171 lm77_write_value(client
, LM77_REG_TEMP_HYST
,
172 LM77_TEMP_TO_REG(data
->temp_hyst
));
173 mutex_unlock(&data
->update_lock
);
177 /* preserve hysteresis when setting T_crit */
178 static ssize_t
set_temp_crit(struct device
*dev
, struct device_attribute
*attr
, const char *buf
, size_t count
)
180 struct i2c_client
*client
= to_i2c_client(dev
);
181 struct lm77_data
*data
= i2c_get_clientdata(client
);
182 long val
= simple_strtoul(buf
, NULL
, 10);
185 mutex_lock(&data
->update_lock
);
186 oldcrithyst
= data
->temp_crit
- data
->temp_hyst
;
187 data
->temp_crit
= val
;
188 data
->temp_hyst
= data
->temp_crit
- oldcrithyst
;
189 lm77_write_value(client
, LM77_REG_TEMP_CRIT
,
190 LM77_TEMP_TO_REG(data
->temp_crit
));
191 lm77_write_value(client
, LM77_REG_TEMP_HYST
,
192 LM77_TEMP_TO_REG(data
->temp_hyst
));
193 mutex_unlock(&data
->update_lock
);
197 static ssize_t
show_alarm(struct device
*dev
, struct device_attribute
*attr
,
200 int bitnr
= to_sensor_dev_attr(attr
)->index
;
201 struct lm77_data
*data
= lm77_update_device(dev
);
202 return sprintf(buf
, "%u\n", (data
->alarms
>> bitnr
) & 1);
205 static DEVICE_ATTR(temp1_input
, S_IRUGO
,
206 show_temp_input
, NULL
);
207 static DEVICE_ATTR(temp1_crit
, S_IWUSR
| S_IRUGO
,
208 show_temp_crit
, set_temp_crit
);
209 static DEVICE_ATTR(temp1_min
, S_IWUSR
| S_IRUGO
,
210 show_temp_min
, set_temp_min
);
211 static DEVICE_ATTR(temp1_max
, S_IWUSR
| S_IRUGO
,
212 show_temp_max
, set_temp_max
);
214 static DEVICE_ATTR(temp1_crit_hyst
, S_IWUSR
| S_IRUGO
,
215 show_temp_crit_hyst
, set_temp_crit_hyst
);
216 static DEVICE_ATTR(temp1_min_hyst
, S_IRUGO
,
217 show_temp_min_hyst
, NULL
);
218 static DEVICE_ATTR(temp1_max_hyst
, S_IRUGO
,
219 show_temp_max_hyst
, NULL
);
221 static SENSOR_DEVICE_ATTR(temp1_crit_alarm
, S_IRUGO
, show_alarm
, NULL
, 2);
222 static SENSOR_DEVICE_ATTR(temp1_min_alarm
, S_IRUGO
, show_alarm
, NULL
, 0);
223 static SENSOR_DEVICE_ATTR(temp1_max_alarm
, S_IRUGO
, show_alarm
, NULL
, 1);
225 static struct attribute
*lm77_attributes
[] = {
226 &dev_attr_temp1_input
.attr
,
227 &dev_attr_temp1_crit
.attr
,
228 &dev_attr_temp1_min
.attr
,
229 &dev_attr_temp1_max
.attr
,
230 &dev_attr_temp1_crit_hyst
.attr
,
231 &dev_attr_temp1_min_hyst
.attr
,
232 &dev_attr_temp1_max_hyst
.attr
,
233 &sensor_dev_attr_temp1_crit_alarm
.dev_attr
.attr
,
234 &sensor_dev_attr_temp1_min_alarm
.dev_attr
.attr
,
235 &sensor_dev_attr_temp1_max_alarm
.dev_attr
.attr
,
239 static const struct attribute_group lm77_group
= {
240 .attrs
= lm77_attributes
,
243 /* Return 0 if detection is successful, -ENODEV otherwise */
244 static int lm77_detect(struct i2c_client
*new_client
,
245 struct i2c_board_info
*info
)
247 struct i2c_adapter
*adapter
= new_client
->adapter
;
248 int i
, cur
, conf
, hyst
, crit
, min
, max
;
250 if (!i2c_check_functionality(adapter
, I2C_FUNC_SMBUS_BYTE_DATA
|
251 I2C_FUNC_SMBUS_WORD_DATA
))
254 /* Here comes the remaining detection. Since the LM77 has no
255 register dedicated to identification, we have to rely on the
258 1. the high 4 bits represent the sign and thus they should
260 2. the high 3 bits are unused in the configuration register
261 3. addresses 0x06 and 0x07 return the last read value
262 4. registers cycling over 8-address boundaries
264 Word-sized registers are high-byte first. */
266 /* addresses cycling */
267 cur
= i2c_smbus_read_word_data(new_client
, 0);
268 conf
= i2c_smbus_read_byte_data(new_client
, 1);
269 hyst
= i2c_smbus_read_word_data(new_client
, 2);
270 crit
= i2c_smbus_read_word_data(new_client
, 3);
271 min
= i2c_smbus_read_word_data(new_client
, 4);
272 max
= i2c_smbus_read_word_data(new_client
, 5);
273 for (i
= 8; i
<= 0xff; i
+= 8) {
274 if (i2c_smbus_read_byte_data(new_client
, i
+ 1) != conf
275 || i2c_smbus_read_word_data(new_client
, i
+ 2) != hyst
276 || i2c_smbus_read_word_data(new_client
, i
+ 3) != crit
277 || i2c_smbus_read_word_data(new_client
, i
+ 4) != min
278 || i2c_smbus_read_word_data(new_client
, i
+ 5) != max
)
283 if (((cur
& 0x00f0) != 0xf0 && (cur
& 0x00f0) != 0x0)
284 || ((hyst
& 0x00f0) != 0xf0 && (hyst
& 0x00f0) != 0x0)
285 || ((crit
& 0x00f0) != 0xf0 && (crit
& 0x00f0) != 0x0)
286 || ((min
& 0x00f0) != 0xf0 && (min
& 0x00f0) != 0x0)
287 || ((max
& 0x00f0) != 0xf0 && (max
& 0x00f0) != 0x0))
294 /* 0x06 and 0x07 return the last read value */
295 cur
= i2c_smbus_read_word_data(new_client
, 0);
296 if (i2c_smbus_read_word_data(new_client
, 6) != cur
297 || i2c_smbus_read_word_data(new_client
, 7) != cur
)
299 hyst
= i2c_smbus_read_word_data(new_client
, 2);
300 if (i2c_smbus_read_word_data(new_client
, 6) != hyst
301 || i2c_smbus_read_word_data(new_client
, 7) != hyst
)
303 min
= i2c_smbus_read_word_data(new_client
, 4);
304 if (i2c_smbus_read_word_data(new_client
, 6) != min
305 || i2c_smbus_read_word_data(new_client
, 7) != min
)
308 strlcpy(info
->type
, "lm77", I2C_NAME_SIZE
);
313 static int lm77_probe(struct i2c_client
*new_client
,
314 const struct i2c_device_id
*id
)
316 struct lm77_data
*data
;
319 data
= kzalloc(sizeof(struct lm77_data
), GFP_KERNEL
);
325 i2c_set_clientdata(new_client
, data
);
327 mutex_init(&data
->update_lock
);
329 /* Initialize the LM77 chip */
330 lm77_init_client(new_client
);
332 /* Register sysfs hooks */
333 if ((err
= sysfs_create_group(&new_client
->dev
.kobj
, &lm77_group
)))
336 data
->hwmon_dev
= hwmon_device_register(&new_client
->dev
);
337 if (IS_ERR(data
->hwmon_dev
)) {
338 err
= PTR_ERR(data
->hwmon_dev
);
345 sysfs_remove_group(&new_client
->dev
.kobj
, &lm77_group
);
352 static int lm77_remove(struct i2c_client
*client
)
354 struct lm77_data
*data
= i2c_get_clientdata(client
);
355 hwmon_device_unregister(data
->hwmon_dev
);
356 sysfs_remove_group(&client
->dev
.kobj
, &lm77_group
);
361 /* All registers are word-sized, except for the configuration register.
362 The LM77 uses the high-byte first convention. */
363 static u16
lm77_read_value(struct i2c_client
*client
, u8 reg
)
365 if (reg
== LM77_REG_CONF
)
366 return i2c_smbus_read_byte_data(client
, reg
);
368 return i2c_smbus_read_word_swapped(client
, reg
);
371 static int lm77_write_value(struct i2c_client
*client
, u8 reg
, u16 value
)
373 if (reg
== LM77_REG_CONF
)
374 return i2c_smbus_write_byte_data(client
, reg
, value
);
376 return i2c_smbus_write_word_swapped(client
, reg
, value
);
379 static void lm77_init_client(struct i2c_client
*client
)
381 /* Initialize the LM77 chip - turn off shutdown mode */
382 int conf
= lm77_read_value(client
, LM77_REG_CONF
);
384 lm77_write_value(client
, LM77_REG_CONF
, conf
& 0xfe);
387 static struct lm77_data
*lm77_update_device(struct device
*dev
)
389 struct i2c_client
*client
= to_i2c_client(dev
);
390 struct lm77_data
*data
= i2c_get_clientdata(client
);
392 mutex_lock(&data
->update_lock
);
394 if (time_after(jiffies
, data
->last_updated
+ HZ
+ HZ
/ 2)
396 dev_dbg(&client
->dev
, "Starting lm77 update\n");
398 LM77_TEMP_FROM_REG(lm77_read_value(client
,
401 LM77_TEMP_FROM_REG(lm77_read_value(client
,
402 LM77_REG_TEMP_HYST
));
404 LM77_TEMP_FROM_REG(lm77_read_value(client
,
405 LM77_REG_TEMP_CRIT
));
407 LM77_TEMP_FROM_REG(lm77_read_value(client
,
410 LM77_TEMP_FROM_REG(lm77_read_value(client
,
413 lm77_read_value(client
, LM77_REG_TEMP
) & 0x0007;
414 data
->last_updated
= jiffies
;
418 mutex_unlock(&data
->update_lock
);
423 static int __init
sensors_lm77_init(void)
425 return i2c_add_driver(&lm77_driver
);
428 static void __exit
sensors_lm77_exit(void)
430 i2c_del_driver(&lm77_driver
);
433 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
434 MODULE_DESCRIPTION("LM77 driver");
435 MODULE_LICENSE("GPL");
437 module_init(sensors_lm77_init
);
438 module_exit(sensors_lm77_exit
);